As a power supply device that receives an input of AC power and drives an electric motor, there has been a power supply device including one route to which electric power for driving the electric motor is input and another route to which electric power for driving a control unit, which controls the power supply device, is input.
A power supply circuit described in Patent Literature 1 described below includes a first converting unit 11 and a second converting unit 12 that convert an AC voltage into a DC voltage. The second converting unit 12 includes a diode D121. An anode of the diode D121 is connected to between an input line L1 and a switch unit S1. A cathode of the diode D121 is connected to a capacitor C1 that supplies a DC voltage applied to a control unit 22. The second converting unit 12 performs half-wave rectification of an AC voltage and charges the capacitor C1. The power supply circuit can supply operation power to the control unit 22 even after the switch unit S1 becomes nonconductive (paragraph 0050 to paragraph 0051 and FIG. 2).